Acoustic Neuroma Causes: What Factors Can Come Into Play

Understanding Acoustic Neuroma

Before discussing what can cause an acoustic neuroma, it’s helpful to have a general understanding of the condition. An acoustic neuroma is a benign tumor that forms from the Schwann cells of the vestibulocochlear nerve. Schwann cells are specialized insulating cells that wrap around the outside of some nerves, like the cranial nerves. There are 12 sets of cranial nerves, which occur in pairs and conduct information to and from the brain. The vestibulocochlear nerve is the eighth cranial nerve and transmits information about hearing and balance.

It’s important to understand that even though an acoustic neuroma is benign, that doesn’t mean it’s harmless. Even a small tumor can cause issues if it presses on other structures, like nerves or blood vessels. Though rare, an acoustic neuroma can even be life threatening if it impinges on the brain stem. This is why it’s important to work with a specialist who can work with you to diagnose and treat your condition.

Acoustic Neuroma Symptoms

Not all acoustic neuromas will cause symptoms. However, if they do occur, symptoms will depend on the size of the tumor, as well as its location along the vestibulocochlear nerve. Some symptoms are related to the impact on the nerve, while others are caused when the tumor presses on other structures. That’s why the symptoms you experience may be different than another person’s. Acoustic neuroma symptoms include:

  • Hearing loss or ringing, typically in one ear
  • A feeling of fullness within the ear
  • Dizziness or vertigo
  • Headaches
  • Nausea
  • Fatigue
  • Blurred vision
  • Facial muscle weakness or numbness
  • A buildup of fluid on the brain (hydrocephalus)

Acoustic Neuroma Causes

Sometimes tumors grow because the gene that tells cells to stop growing isn’t functioning properly. Researchers believe that a gene on chromosome 22 stops working in some individuals, leading to uncontrolled Schwann cell proliferation and acoustic neuroma formation. What’s not well understood is what causes the governor gene to stop working.

Around 5% of the time, the defective gene is inherited, causing a rare condition called neurofibromatosis type 2 (NF 2). Individuals with NF 2 typically have bilateral acoustic neuromas, along with other tumors throughout the body. However, most acoustic neuromas are spontaneous (not inherited) and occur on only one side of the body.

What can cause the spontaneous proliferation of Schwann cells? Studies have been done to explore possible causes. There is only one factor that has been definitively linked with acoustic neuroma development: very high doses of radiation therapy to the head during treatment of a medical condition, like cancer.

Another potential cause of acoustic neuroma is loud noise exposure. This includes both occupational (like machinery and power tools) to nonoccupational exposure (like loud music). There hasn’t been enough evidence to establish a definitive link, but some studies have found evidence that loud noise exposure may be a contributing factor. 

If you’ve been diagnosed with acoustic neuroma, one question to cross your mind might be, “How did this happen?” Unfortunately, there’s no clear answer. However, clinicians and researchers are working hard to understand what can cause acoustic neuroma and have uncovered some of the factors that can come into play. Read on to learn what is known about the cause of acoustic neuroma so you can begin to understand more about your condition.

Treating Acoustic Neuroma

The good news is that the cause of your acoustic neuroma may not be well understood, but there are effective, proven treatment options available. Not everyone with an acoustic neuroma will require treatment immediately. If your acoustic neuroma is small and not causing symptoms, your doctor may recommend careful monitoring for changes. However, if your doctor does recommend intervention, there are different options available.

Some patients will require surgical removal of all or part of their acoustic neuroma. This may be the case if a tumor is very large or in younger patients. Surgery does require a hospital stay, followed by a recovery period while your body heals, typically 4-8 weeks. Microsurgical options are now available that are less invasive than traditional surgery but still require a hospital stay and recovery at home.

Another treatment option is Gamma Knife radiosurgery, an advanced form of radiation therapy that can shrink your tumor while sparing healthy neighboring cells. Gamma Knife radiosurgery takes place while you are awake, doesn’t involve any incisions or a hospital stay and is followed by a brief recovery period of a day or two. It can be an excellent treatment option for acoustic neuroma if you cannot undergo surgery, your tumor is difficult to reach or could only be partially removed. Gamma Knife radiosurgery is also a good choice for patients who simply prefer a minimally invasive treatment option.

Understanding Your Condition

Unfortunately, there’s probably not an easy answer to what has caused your acoustic neuroma. Researchers and clinicians are working hard to understand more about acoustic neuroma and uncover more information with each new study. However, regardless of the cause of your condition, there are excellent treatment options available with proven results.

Learning you have a brain tumor has undoubtedly been a stressful process for you. Taking the time to understand your condition is a powerful way to play an active role in your care. Educating yourself and discussing things with your doctor can help eliminate some of the unknowns, giving you more confidence as you move forward. Keep the conversation going with your doctor, who can help answer any lingering questions you may have. It will help set your mind at ease so you can focus your energy on what matters most: getting better.

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